Formation of open coil with spacer band

ABSTRACT

Process and means are disclosed for forming an open coil of strip metal, such as steel strip, in which the convolutions of the coil are spaced apart to permit passage of treating gases through the spaces for treating the material of the strip. A spacer band or web is interwound with the strip as it is wound into a coil to achieve the desired spacing of the convolutions, the spacer being substantially the same width as the strip and having elongated members extending transversely of the strip which are stiff enough to restrict undesirable bending of the strip across its width. The spacer also includes elongated members that extend generally longitudinally of the strip and that are flexible enough to form the coil. The spacer band acts as a structural member that supports the metal strip during forming and handling of the open coil and during treating of the strip, and thus promotes the successful formation, handling, and treatment of open coils of very thin metal, for example steel strip as thin as 0.003 inch in thickness.

United States Patent 11 1 Iszczukiewicz 1 1 Dec. 2, 1975 [75] Inventor:Ludwig C. Iszczukiewicz, Maple Heights, Ohio [73] Assignee: Lee WilsonEngineering Company,

Inc., Cleveland, Ohio [22] Filed: Dec. 3, 1973 [21] Appl. No.: 420,917

[52] U.S. Cl. 148/16; 148/6.35;148/14;

148/16.7; 148/20.3; 148/156; 242/781 [51} Int. Cl. C2lD l/74; C21D 9/68[58] Field of Search 148/16, 16.7, 155, 156,

Primary E.taminerC. Lovell Attorney, Agent, or FirmBosworth, Sessions &McCoy [57] ABSTRACT Process and means are disclosed for forming an opencoil of strip metal, such as steel strip, in which the convolutions ofthe coil are spaced apart to permit passage of treating gases throughthe spaces for treating the material of the strip. A spacer band or webis interwound with the strip as it is wound into a coil to achieve thedesired spacing of the convolutions, the spacer being substantially thesame width as the strip and having elongated members extendingtransversely of the strip which are stiff enough to restrict undesirablebending of the strip across its width. The spacer also includeselongated members that extend generally longitudinally of the strip andthat are flexible enough to form the coil. The spacer hand acts as astructural member that supports the metal strip during forming andhandling of the open coil. and during treating of the strip, and thuspromotes the successful formation, handling. and treatment of open coilsof very thin metal, for example steel strip as thin as 0.003 inch inthickness.

6 Claims, 6 Drawing Figures US. Patent Dec. 2, 1975 3,923,556

FORMATION OF OPEN COIL WITH SPACER BAND BACKGROUND OF THE INVENTION Thisinvention relates to the annealing or other treating of strip metal inwhich the strip is wound into an open coil in which the convolutions ofthe coil are spaced apart and treating gases are passed between theconvolutions to effect treatment of the metal of the strip; and moreparticularly this invention relates to process and means for spacingapart the convolutions in the coil and maintaining the stability andform of the open coil during processing and handling.

The invention will be disclosed hereafter in connection with the formingof open coils of steel strip for such treating purposes since itprovides exceptional advantages in such use, although it may be used forforming open coils of other strip material.

In the treating, as annealing, of steel strip in which the strip iswould into an open coil, the open coil is heated to as high as 1750F. bypassing a suitable heated atmosphere through the spaces between theconvolutions of the coil, as by the process and apparatus disclosed inWilson & Corns US. Pat. 3,114,539. Other open coil treatments mayinvolve modifying the chemical composition of the strip metal. Forexample, the carbon content of steel strip may be modified by the use ofa suitable atmosphere. Furthermore, treatments may involve oxidation,bright annealing, gas alloying, and treatments involving the applicationto the surfaces of the strip metal materials that will react withconstituents of the metal and the treatment of the surfaces by passingheated gases between the spaced strip convolutions. The Lee Wilson US.Pat. 3,109,877 discloses advantageous methods of modifying thecomposition of the metal, which can be used in conjunction with thepresent invention.

Various processes and means have been used or proposed to separate theconvolutions of a strip wound in an open coil, and to keep theconvolutions separated during coiling, handling, and treating of thecoil.

The problem is considerably more difficult when the strip is of lightgauge, as from about 0.003 inch to 0.035 inch thick, and when the stripis of substantial width as from about 18 inches to as much as 72 inches.Strip steel of such small thicknesses and substantial width may bend ordistort during the forming or handling of the open coil and change inform during the heat treatment due to thermal effects. Such distortionmay cause the convolutions to contact each other so that all parts ofthe strip do not receive uniform treatmentand the quality of the productmay be reduced by distortion of the coil.

SUMMARY OF THE INVENTION The invention comprises a process of forming anopen coil of metal strip in which the convolutions of the strip in thecoil are spaced to permit passage of gas therebetween, comprisingwinding the strip into a coil simultaneously with a longtudinal spacerband or web so that the spacer band is located between the convolutionsof the strip. The spacer band is of substantial width, being at least aswide as a major portion of the width of the strip and preferably issubstantially as wide as the strip for maximum support of the strip. Theband is sufficiently longitudinally flexible to be wound be tween theconvolutions of the strip in the coil. Transversely of the strip theband is sufficiently stiff to resist transverse bending of the strip andresulting distortion of the coil. The spacer band is formed of spacedinterconnected elongated metal elements that are laterally offset topermit adequate flow of gas between adjacent convolutions of the coiltransversely of the convolutions, i.e., axially of the coil. Theinvention also comprises a method of treating coils of strip with agaseous atmosphere in an open coil treating operation, the convolutionsof the open coil being spaced by such a spacer band. The invention alsocomprises an open coil of metal strip having such a spacer bandincorporated therein, and such a spacer itself.

The spacer band acts as a structural element contacting a large area ofthe metal strip during the winding of the coil, during handling of thecoil, and during treatment. This structural element prevents distortionof the convolutions of the coil that could cause them to contact eachother and produce the above indicated disadvantages. The spacer bandelement can be recovered and reused on rewinding of the open coil into atight coil.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other advantages andfeatures of the invention will be apparent from the followingdescription of the invention in connection with the accompanyingdrawings in which:

FIG. 1 illustrates the winding of an open coil with a spacer bandembodying the invention between the convolutions of the coil;

FIG. 2 is a perspective showing a portion of a preferred spacer bandembodying the invention, to a scale larger than that of FIG. 1;

FIG. 3 is a perspective to an enlarged scale of a portion of the opencoil of FIG. 1 showing spaced coil convolutions separated by a preferredspacer band embodying the invention, the thicknesses of the metal stripand the spacer band being exaggerated for clarity;

FIG. 4 is a section along line 4-4 of FIG. 3 ofa portion of an open coilembodying the spacer band of FIG. 3 between the convolutions of thecoil, the scale being larger than that of FIG. I;

FIG. 5 is a side view of another form of spacer band embodying theinvention that may be used according to the invention; and

FIG. 6 is a cross sectional view similar to FIG. 3 but showing a portionof a coil embodying the invention and embodying the spacer band of FIG.5.

DESCRIPTION OF PREFERRED EMBODIMENTS In FIG. 1, a strip of metal Semanating from a suitable source, such as a conventional. tightly woundcoil C of strip of the desired thickness and width, that is supported ona known rotatable payoff turntable 1, comprising a generally flat discportion 2 and central mandrel 3, supported for rotation about a verticalaxis. The strip S passes from coil C to a coil C' that is supported on aknown power-driven rotatable turntable 4 mounted for rotation about avertical axis and comprising a generally flat disc portion 5 and a knowncollapsible mandrel 6. The strip is thus rewound into an open coil Chaving spaced convolutions X.

Disposed between the freely rotatable payoff tumtable 1 and the powerdriven recoiling turntable 4 is a known tension control apparatus 7which is adapted to impose the desired amount of back-tension on thestrip that is being recoiled. Apparatus of this type is disclosed in theabove noted Wilson and Corns US Pat. No. 3,114,539 which is incorporatedherein by reference to the extent that its disclosure is applicable.Another turntable 8, supported for rotation about a vertical axis,includes a disc portion 9 and a suitable mandrel 10. A coil C" of spacerband Y embodying the invention, in this embodiment is substantially aswide as the strip S, passes between guide rollers 12 and is wound intothe coil C between the convolutions X of the coil.

A portion of the spacer band Y of FIG. 1 is shown in FIG. 2. Itcomprises a reticulated structure made up of spaced substantiallyparallel elonated members such as wires 13 that extend transversely ofthe strip S, connected to spaced substantially parallel elongatedmembers such as wires 14 that extend longitudinally of the strip S whenthe spacer is in place. The wires 13 are fixed as by spot welding towires 14 in such manner that there are no sharp edges or protrusionsthat can scratch or otherwise harm the surfaces of the convolutions ofthe coil. Furthermore, it is preferable, as is shown in FIGS. 2 and 3,that wires 13 are all on one side of the longitudinally extendingwiresl4so that, as shown in FIG. 3, when the spacer band Y is locatedbetween the convolutions X of the coil and the coil is being treated inan oven by passage of heated gas between the convolutions of the coil,there is substantially unimpeded flow of the treating gas between theconvolutions, as is shown by the arrows G. The only contacts between theconvolutions of the coil and the spacer occur where the members 13 and14 contact the convolutions. Preferably, as is shown, the cross sectionsof the members 13 and 14 are circular; this makes possible lower costconstruction because these parts can be made of readily available wireor rod, and makes possible minimal contacts of the spacer with theconvolutions of the coil because of the contacts provided by thecircular cross secitonal members 13 and 14 have essentially only linecontacts with the surfaces of the metal strip forming the coilconvolutions.

Preferably, transverse members 13 and longitudinal members 14 aresufficiently stiff that during winding, handling, heat treatment,cooling, and subsequent handling of the open coil the wires support theconvolutions of the strip from undersirable bending and distortion.Furthermore, the longitudinal members 14 are sufficiently flexible sothat they permit the spacer band to be readily wound between theconvolutions of the coil without damaging them. It is preferable thatthe members 13 be stiffer than the longitudinal members 14 so the bandis stiffer and substantially less flexible transversely thanlongitudinally of the metal strip forming the coil convolutions.

The spacer band Y is preferably formed of metal which resists corrosion,does not react or stick to the metal of the strip in the convolutions,and lends itself to reuse. For these reasons stainless steel mayadvantageously be used.

While the spacer band of FIG. 2 is practicable and of relatively lowcost, other types of spacer bands may be used in the invention, such asspacer band Z shown in FIGS. and 6. This spacer is similar to a type ofknown conveyor belt. It comprises substantially parallel elongatedmembers 16 which may take the form of stiff rods or wires that areconnected by members 17 that extend generally longitudinally of the bandand hence of the strip. Members 17 are flattened helices, the vertices18 of which are looped between the vertices of the flattened helicesformed by adjacent members 17 with the transverse members 16 extendingthrough the loops 18 thus formed. The spacer band Z thus issubstantially flexible longitudinally and substantially stifftransversely of the spacer band and of the strip.

When interwound between the convolutions of a coil, as by the apparatusand process illustrated by FIG. 1, the resulting open coil has thespacer Z between the convolutions thereof, and a substantiallyunobstructed gas flow is permitted. As shown, the members 16 and 17 areof circular cross section and thus each of these members makes onlyminimal contact with the surfaces of the strip convolutions, so that thegas atmosphere can contact essentially the entire surface of theconvolutions for treatment purposes. This form of spacer band is alsopreferably made of stainless steel or other material that is heat andcorrosion resistant, that will not react with the metal of the strip X,and that may be recovered on rewinding of the open coil into a tightcoil and be re-used again.

By use of a spacer band embodying the invention, such as either of thoseillustrated above, preferably where the spacer extends substantially forthe full width of the strip, strips of steel or other metal ofsubstantial width and quite thin can be successfully wound into opencoils that can be handled and heat treated, without material bending,collapsing or contacting of the convolutions which would causedegradation in quality. The spacer itself contacts the convolutions insmall areas which are spaced across the sufficiently long and wide areasof the convolutions sufficiently closely to prevent such bending .orcollapsing, but sufficiently widely not to interfere with the action ofthe treating gas on the convolutions of the strip in the open coil. Awide range of such spacings is possible. The spacer thus acts as astructural element of the open coil, not only in spacing the individualconvolutions but also as an internal support for the open coil as awhole.

The thickness of the spacing element and of the members making it islargely dependent on the width and thickness of the strip metal to bewound into an open coil. In general, to permit as large a length ofstrip as possible to be heated in a given treating furnace, the spacershould be as thin as possible consistent with the function ofmaintaining adequate space between the convolutions of the open coil ofstrip to permit essentially complete access of the desired volume oftreating gas to all portions of the strip while preventing bending orcollapsing of the convolutions relative to adjacent convolutions thatcould degrade quality. A spacer of the type shown in FIGS. 1 and 2having members 13 spaced about 2 inches apart and members 14 about 2%inches apart has been successfully used.

The invention also makes possible tighter winding in open coils of metalstrips than would otherwise be possible. And this also aids inmaintaining the shapes of the convolutions and coil during the heating.

As previously noted, the invention provides particular benefits whenused with metal strips about 0.003 inch to about 0.035 inch thick andespecially about 0.008 inch to about 0.035 inch thick, and from about 18inches to about 72 inches wide, at treating temperatures ranging fromabout ll00F. to about 1750F. if the strip is steel, depending on thenature of the treatment to be applied and the composition of the strip.

While the invention has been disclosed having particular advantage inthe treatment of very thin metal strip. it may also be used to advantagewith thicker strip.

It will also be understood that the invention may be applicable not onlyto annealing of metal strip, but also to modification of the chemicalcomposition and metallurgical structure by treatment of an open coil inwhich the spacer band is present. Various modifications apparent tothose skilled in the art, in addition to those indicated, may be made inthe apparatus, methods and articles indicated above, and changes may bemade with respect to the features disclosed, provided that the elementsset forth in any of the following claims or the equivalents of such beemployed.

What is claimed is:

1. In the process of heat treating metal strip in an open coil whichcomprises coiling metal strip into an open coil in which theconvolutions of the strip in said coil are spaced to permit passage oftreating gas therebetween, said strip being of such small thickness andof such substantial width relatively to said thickness that when saidtreating gas is passed between said convolutions of said open coiladjacent convolutions of said strip in said coil can bend, distort, orchange form sufficiently to cause said convolutions to contactsufficiently to impair substantially the uniformity of treatment by saidgas and the quality of the treated strip unless said adjacentconvolutions are kept separated over a major portion of the width ofsaid strip and thereafter during such heat treatment passing a treatinggas between said spaced convolutions of said strip, the improvementwhich comprises winding the strip into a coil simultaneously with alongitudinal spacer so that the spacer is located between adjacentconvolutions of the strip, the spacer comprising a band that is at leastas wide as a major portion of the width of said strip, thatlongitudinally of said band is sufficiently flexible to be wound betweenthe convolutions of said strip in said coil and transversely thereof issufficiently wide and stiff to restrict the convolutions of the coilseparated by said spacer band from bending transversely thereofsubstantially throughout at least a major portion of the width of thestrip, said spacer band being formed of spaced substantially parallelelongated members extending transversely of said spacer band, and spacedelongated members extending generally longitudinally of said spacer bandand connected to said members extending substantially transversely ofsaid spacer band, said members being relatively laterally offset topermit adequate flow of said gas between adjacent convolutions of saidcoil transversely of said convolutions, and contacting and supportingsaid spaced convolutions at a plurality of locations sufficientlyclosely spaced essentially to prevent contact of adjacent convolutionswith each other, and being free of sharp edges or protrusions that canharm the surfaces of said strip in said coil convolutions.

2. A process of heat treating an open coil of metal strip in which theconvolutions of strip are spaced to permit passage of treating gastherebetween by a spacer band that is interwound between adjacentconvolutions of said strip of said coil, said strip being of such smallthickness and of such substantial width relatively to said thicknessthat when said strip is wound into an open coil having spacedconvolutions between which said treating gas is passed adjacentconvolutions of said strip in said coil can bend, distort, or changeform sufficiently to cause said convolutions to contact sufficiently toimpair substantially the uniformity of treatment by said gas and thequality of the treated strip unless said adjacent convolutions are keptseparated over a major portion of the width of said strip, said spacerband being at least as wide as a major portion of the width of saidstrip and longitudinally thereof being sufficiently flexible to be woundbetween the convolutions of said coil and transversely thereof beingsufficiently wide and stiff to restrict the convolutions of said coilfrom bending transversely thereof throughout at least a major portion ofthe width of said strip, said spacer band being formed of spacedsubstantially parallel elongated members extending substantiallytransversely of said spacer band, and spaced elongated members extendinggenerally longitudinally of said spacer band and connected to saidmembers extending substantially transversely of said spacer band, saidmembers being relatively laterally offset so as to permit substantiallyunimpeded flow of gas between adjacent convolutions of said coiltransversely of said convolutions, and contacting and supporting saidspaced convolutions at a plurality of locations sufficiently closelyspaced essentially to prevent contact of adjacent convolutions with eachother, and being free of sharp edges or protrusions that can harm thesurfaces of said strip in said coil convolutions, which processcomprises subjecting the open coil to heat treatment during whichtreating gas is passed between said spaced convolutions of said strip insaid open coil.

3. The process of claim 2 in which said spacer band is substantially aswide as said metal strip.

4. The process of claim 2 in which said spacer band acts as a structuralsupport for the convolutions of said strip in said coil.

5. The process of claim 2 in which said substantially transverselyextending elongated members are all on one side of said generallylongitudinally extending elongated members.

6. The process of claim 2 in which in said spacer band said generallylongitudinally extending elongated mambers connecting said spacedtransverse elongated members are metal of generally flat helicalconfiguration with spaced vertices connected to adjacent transversemembers, each transverse member being in a loop formed by engagedvertices of two adjacent flattened helices, the portions of the helicesbetween the generally transverse members being offset from said geneallytransverse members.

1. IN THE PROCESS OF HEAT TREATING METAL STRIP IN AN OPEN COIL WHICHCOMPRISES COILING METAL STRIP INTO AN OPEN COIL IN WHICH THECONVOLUTIONS OF THE STRIP IN SAID COIL ARE SPACED TO PERMIT PASSAGE OFTREATING GAS THEREBETWEEN, SAID STRIP BEING OF SUCH SMALL THICKNESS ANDOF SUCH SUBSTANTIAL WIDTH RELATIVELY TO SAID THICKNESS THAT WHEN SAIDTREATING GAS IS PASSED BETWEEN SAID CONVOLUTIONS OF SAID OPEN COILADJACENT CONVOLUTIONS OF SAID STRIP IN SAID COIL CAN BEND, DISTORT, ORCHANGE FORM SUFFICIENTLY TO CAUSE SAID CONVOLUTIONS TO CONTACTSUFFICIENTLY TO IMPAIR SUBSTANTIALLY THE UNIFORMITY OF TREATMENT BY SAIDGAS AND THE QUALITY OF THE TREATED STRIP UNLESS SAID ADJACENTCONVOLUTIONS ARE KEPT SEPARATED OVER A MAJOR PORTION OF THE WIDTH OFSAID STRIP AND THERAFTER DURING SUCH HEAT TREATMENT PASSING A TREATINGGAS BETWEEN SAID SPACED CONVOLUTIONS OF SAID STRIP, THE IMPROVEMENTWHICH COMPRISES WINDING THE STRIP INTO A COIL SIMULTANEOUSLY WITH ALONGITUDINAL SPACER SO THAT THE SPACER IS LOCATED BETWEEN ADJACENTCONVOLUTIONS OF THE STRIP, THE SPACER COMPRISING A BAND THAT IS AT LEASTAS WIDE AS A MAJOR PORTION OF THE WIDTH OF SAID STRIP, THATLONGITUDINALLY OF SAID BAND IS SUFFICIENTLY FLEXIBLE TO BE WOUND BETWEENTHE CONVOLUTIONS OF SAID STRIP IN SAID COIL AND TRANSVERSELY THEREOF ISSUFFICIENTLY WIDE AND STIFF TO RESTRICT THE CONVOLUTIONS OF THE COILSEPARATED BY SAID SPACER BAND FROM BEING TRANSVERSELY THEREOF SUB-
 2. Aprocess of heat treating an open coil of metal strip in which theconvolutions of strip are spaced to permit passage of treating gastherebetween by a spacer band that is interwound between adjacentconvolutions of said strip of said coil, said strip being of such smallthickness and of such substantial width relatively to said thicknessthat when said strip is wound into an open coil having spacedconvolutions between which said treating gas is passed adjacentconvolutions of said strip in said coil can bend, distort, or changeform sufficiently to cause said convolutions to contact sufficiently toimpair substantially the uniformity of treatment by said gas and thequality of the treated strip unless said adjacent convolutions are keptseparated over a major portion of the width of said strip, said spacerband being at least as wide as a major portion of the width of saidstrip and longitudinally thereof being sufficiently flexible to be woundbetween the convolutions of said coil and transversely thereof beingsufficiently wide and stiff to restrict the convolutions of said coilfrom bending transversely thereof throughout at least a major portion ofthe width of said strip, said spacer band being formed of spacedsubstantially parallel elongated members extending substantiallytransversely of said spacer band, and spaced elongated meMbers extendinggenerally longitudinally of said spacer band and connected to saidmembers extending substantially transversely of said spacer band, saidmembers being relatively laterally offset so as to permit substantiallyunimpeded flow of gas between adjacent convolutions of said coiltransversely of said convolutions, and contacting and supporting saidspaced convolutions at a plurality of locations sufficiently closelyspaced essentially to prevent contact of adjacent convolutions with eachother, and being free of sharp edges or protrusions that can harm thesurfaces of said strip in said coil convolutions, which processcomprises subjecting the open coil to heat treatment during whichtreating gas is passed between said spaced convolutions of said strip insaid open coil.
 3. The process of claim 2 in which said spacer band issubstantially as wide as said metal strip.
 4. The process of claim 2 inwhich said spacer band acts as a structural support for the convolutionsof said strip in said coil.
 5. The process of claim 2 in which saidsubstantially transversely extending elongated members are all on oneside of said generally longitudinally extending elongated members. 6.The process of claim 2 in which in said spacer band said generallylongitudinally extending elongated mambers connecting said spacedtransverse elongated members are metal of generally flat helicalconfiguration with spaced vertices connected to adjacent transversemembers, each transverse member being in a loop formed by engagedvertices of two adjacent flattened helices, the portions of the helicesbetween the generally transverse members being offset from said geneallytransverse members.